Spring sash balance



A. F. MANTZ SPRING SASH BALANCE Filed June 19, 1939 [III],

May 20, 1941.

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,T 20 16 m m Patented May 2 0, 1941 UNITED STATES OFFICE 4 Claims.

My invention relates generally to spring sash balances, particularly ofthe type patented by me February 21, 1933, No. 1,898,584, also No.2,117,896 issued May 17, 1938, and my co-pending application for U. S.Letters Patent filed July 5, 1938, Serial No. 217,407.

The principal objects of my present invention are, to generally improveupon and simplify the construction of the spring sash balances: formingthe subject matter of the above mentioned patents and pending patentapplication, as well as other similar forms of spring sash balances, andfurther, to provide comparatively simple, practical, and easily operatedmeans for winding the spiral springs of the balances so as toeifectively and accurately regulate the tension thereof.

Further objects of my invention are, to provide in a spring sash balancea simplified and compact construction for regulating the tension of thesprings and which improved construction minimizes the production costsof the balances and further, to provide spring tension adjusting meanswhich after operation of the principal adjusting element, the latter andthe spring are securely locked so as to make the tension adjustmentpermanent and unchangeable and further, to provide spring tensionadjusting means that is operative only to increase, not decrease thetension, therebt eliminating trouble and inconvenience while installingthe balance.

A further object of my invention is, to provide sash balance springtensioning means which will efiectively prevent the spring from beingunwound by mechanics or workmen engaged in installing the balances and,also preventing the adjusting means from slipping while the spring isbeing wound to develop the required degree of tension.

With the foregoing and other objects in view, my invention consists incertain novel features of construction and arrangement of parts: thatwill be hereinafter more fully described and claimed and illustrated inthe accompanying drawing in which:

Fig. 1 is an elevational view of the upper portion of a sash balancehousing, looking against the face plate thereof and with a portion ofthe housing broken away and in section.

Fig. 2 is a vertical section taken on the line 22 of Fig. 1.

Fig. 3 is a vertical section taken on the line 33 of Fig. 2.

Fig. 4 is a. perspective view of the tubular spindie that is mounted forrotation in the housing and which is connected to the inner end of thespiral spring that is arranged within and connected to the cable windingdrum.

Fig. 5 is an elevational view of a portion of the rear side of the sashbalance housing and showing the parts seen looking in the directionindicated by the arrow 5 in Fig. 2.

Fig. 6 is an enlarged detail section taken approximately on the line 6-6of Fig. 2.

Referring by numerals to the accompanying drawing which illustrates apreferred embodiment of my invention, It designates the face plate whichis secured in any suitable manner to the front edges of the continuousside and end walls ll of the housing and, which side and end wall-s arepreferably formed integral with and disposed at right angles to the rearwall [2.

A circular portion of the rear wall I2 is pressed inwardly to form ashort circular stud l3 that provides a bearing for the rear end of thetubular spindle hereinafter more fully described and, formed through theface plate Ill in transverse alignment with the bearing member or studI3 is an aperture M for the accommodation of the forward end of thetubular spindle.

Formed integral with and projecting inwardly from the face plate Itaround the aperture I4 is a flange [5 that provides a bearing for theforward portion ofthe tubular spindle.

Mounted for rotation on the bearing member or stud I3 is the rearportion of the main body I 6 of the tubular spindle, the forward portionll thereof being slightly reduced in diameter and arranged for rotationin the bearing formed by the inwardly presented flange 15. The forwardend of this tubular spindle is closed by an integral plate l8 and,formed in the latter is a slot 19 or a non-circl'i-l'ar opening adaptedto receive the point of a screw driver or like implement that isutilized for rotating the tubular spindle when spring adjustments aremade.

Formed in the rear wall l2 of the housing immediately adjacent thebearing stud l3 and concentric therewith is a plurality of, preferablythree, short arcuate slots 29 which receive arouate ratchet teeth2| thatare formed on the rear end of tubular Spindle IS. The depth of theseratchet teeth is such that their pointed ends normally project slightlybeyond the outer face of rear'wall I2 of the housing.

The drum that carries the cable or tape of the fixture is preferablyformed from. a single piece of sheet metal and comprises a disc 22having a marginal flange 23 that is channel-shape in cross section thatreceives the convolutions of the cable. or tape that is carried by saiddrum. In

the present instance, I have shown the drum provided with a cable, oneend thereof being fixed to the flange of the drum and the other enddetachably secured by conventional means to the window sash with whichthe balance is associated.

Formed in the center of the disc 22 of the drum is a circular opening 24for the accommodation of the inwardly presented flange I around openingI4 and, formed integral with the disc 22 adjacent the opening therein isan inwardly presenlted flange 25 that bears upon said flange I5 duringrotation of the cable carrying drum.

The outer end of a spiral spring 26 is connected in any suitable mannerto flange 23 on the inner face thereof and, the inner'end of this springis connected in any suitable manner to the tubular spindle I6.

In Fig. 3 I have illustrated the inner end of the spring 26 formed intoa hook 21 that engages through a short longitudinally disposed slot 28that is formed in spindle I6. After the parts of the balance have beenassembled and it is desired to wind spring 26 so as to impart thedesired de-- gree of tension thereto, the point of a screw driver orsuitable tool is inserted in aperture I9 in the forward end of thetubular spindle l6 and the latter is rotated by imparting turningmovement to the tool.

Due to the arrangement of the ratchet teeth 2| in the arcuate slots 20,the spindle can be rotated in only one direction and thus, a carelessworkman or person not having a complete understanding of the. balanceand particularly the operation necessary to impart tension to thespring, may wind the spring only in one direction and which is theproper direction in which to wind the convolutions of the spring aboutthe spindle so as to increase the tension of said spring. Further, thisparticular construction prevents slipping and reverse rotary movement ofthe spindle while the same is being rotated to wind the spring.

While rotary movement is imparted to the spindle to Wind the spring theteeth 2| must necessarily move from one aperture 20 to the other and,during such movement the comparatively long inclined faces of theratchet teeth 2| bear on the rear wall of the housing I2 between theopenings '20 therein, therebyproducing sufiioient pressure against therear wall I2 and also against the flange IS on the face plate to causesaid rear wall and face plate to flex outwardly a suflicient distance topermit the high points of the teeth to readily pass from one opening '29to another.

Inasmuch as the face plate I0 and rear wall l2 of the housing are formedfrom thin sheet metal having a certain degree of resiliency, thisflexing movement takes place without permanent distortion of the faceplate and rear wall and Without in any way afiecting the properfunctioning of the spring carrying spindle.

Under normal conditions the points of the-teeth 2| project slightlybeyond the outer face of the rear wall |'2 of the housing and, if it isfound desirable to secure the spindle against rotation after the properdegree of tension has been imparted to the spring 26, the projectingends of the teeth 2| may be upset in either direction radially of the:axis of the spindle, asshown by dotted lines a Fig. 5, and when thusupset and riveted down, it is impossible for the'spindle I6 to berotated in either direction.

Thus it will be seen that I haveprovide'd a spring sash balance andparticularly spring tension adjusting means that is relatively simple inconstruction, inexpensive of manufacture and very eflective inperforming the functions for which it is intended.

It will be understood that minor changes in the size, form andconstruction of the various parts of my improved spring sash balance,may be made and substituted for those herein shown and described,without departing from the spirit of my invention, the scope of which isset forth in the appended claims.

I claim as my invention: 1. In a spring sash balance, a housing havingfront and rear walls at least one of which is characterized by aspring-like flexibility, a spindle bearing in one of the said walls andradially arslots and the other end in thebearing, a drum mounted forrotation about the spindle, a spiral spring within the drum having oneend connected to the spindle and the otherend to the drum, means carriedon the periphery ofsaid drum for attachment to a sash, and means forapplying a tool to turn the spindle for tensioning the spring, thethrust member being adapted to exert an outward pressure on the Walls toflex at least one of the same as the ratchet teeth pass throughsuccessive slots in their path of rotation;

2. In a spring sash balance, a housing having front and rear walls atleast one of which is characterized by a spring-like flexibility, aninturned annular flange on one wall defining a spindle bearing, radiallyarranged slots in the other wall, the bearing and arrangement of theslots having a common axis, a spindle formed with a thrust member at oneend, and ratchet teeth at the other, the spindle being mounted with theratchet teeth engaging the slots and the other end in the bearing, adrum mounted for rotation about the spindle, a spiral springwithin thedrum having one end connected to the spindle and the other end to thedrum, means carriedon the periphery of said drum for attachment to asash, and means for applying a tool to turn the spindle for tensioningthe spring, the thrust member being adapted to exert an outward pressureon the walls to flex at least one of the same as the ratchet teeth passthrough successive slots in their path of rotation.

3. In a spring sash balance, a housing having front and rear walls atleast one of which is characterized by a spring-like flexibility, one ofthe walls being provided with an inturned annular flange defining aspindle bearing and a drum bearing, radially arranged slots in the otherwall, the-bearings and arrangement of theslots having a common axis, aspindle formed with a thrust member at one end and ratchet teeth at theother, the spindle being mounted with the ratchet teeth engaging theslots and the other end in the spindle bearing, a drum mounted on thedrum bearing for rotation about the spindle, a spiral spring within thedrum having one end connected to the spindle and the other end to thedrum, means carried on the periphery of said drum for attachment to asash, and means for applying a tool to turn the spindle for tensioningthe springs, the thrust member beingadapted to exert an outward pressure'on the walls to flex at least one of thesame as the ratchetteeth passthrough successive slots in-their path of ro- V other end engaging thesaid slots, a drum mounted for rotation about the spindle, a spiralspring within the drum having one end connected to the spindle and theother end to the drum, means carried on the periphery of said drum forattachment to a sash, and means for applying a tool to turn the spindlefor tensioning the spring, the said shoulder being adapted to exert anoutward thrust on the Walls to flex at least one of the same as theratchet teeth pass through successive slots in their path of rotation.

ADOYSIUS F. MANTZ.

